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Discussion Starter · #1 ·
Scrolling thru the threads, I have found similar circumstances; however, none are quite like mine.

2007 9-3 Aero 2.8t V6, 126K for mileage.

6-speed stick.

I have brand new OEM coils and plugs.

The tach stays nice and smooth and the engine is smooth, no bucking or stuttering at all.

The boost gauge will act normal under acceleration; however, will shoot right over to red as if I was bouncing the car off its rev limiter. It will do this constantly.

There is no CEL present and the car does not go in limp mode.

I will come to a red light and do it all over again, this time the car acts 100% normal.

Would this sound like a boost control valve issue? Your thoughts.
 

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"The boost gauge will act normal under acceleration; however, will shoot right over to red as if I was bouncing the car off its rev limiter. It will do this constantly."

Not following.... it shoots to red when?
 

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Discussion Starter · #3 ·
it shoots in red when I apply the gas pedal. Normally when I do this the boost needle hugs the start of the red section. However, every now and again I apply the gas pedal and the boost needle clears right into the red and bounces in the red zone as if it were trying to self-correct but it can not.
 

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The puzzling thing here is that is sounds like the car performs normally AND the boost gauge goes into the red.

Or, is there a surge of power that normally you would not have?

The only time my 2.8 goes into the red is after I had an increase in horsepower after Vtuner made modifications. Stock, the car would never go into anything past white and it only goes red if I floor it and let it go to the max shift points.

No extra surge huh? :confused:
 

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Boost Pressure Control Valve? A $75 part and 5 minutes to change.
Another common weakness in the V6.
 

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Do you back off when you get that surge? I have noticed the v6 motor (and probably the 4cyl as well) is very touchy about overboost. If you do back off, try doing it again, but this time keep the throttle applied. if it truly is overboosting, it will throw the car into limp mode and pop up a code. Then you will know for sure if it's the boost controller or not.
 

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Has your idle been rough? You could have a dirty maf if it hasn't been cleaned in a while, grab a can of CRC MAF cleaner for 6 bucks and start there before you buy a bunch of new parts and stuff. If the maf has buildup and is dirty, that could cause surging.

Although I still have no idea what that turbo gauge actually even represents... to me it's more eye candy than it is help...lol
 

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Has your idle been rough? You could have a dirty maf if it hasn't been cleaned in a while, grab a can of CRC MAF cleaner for 6 bucks and start there before you buy a bunch of new parts and stuff. If the maf has buildup and is dirty, that could cause surging.

Although I still have no idea what that turbo gauge actually even represents... to me it's more eye candy than it is help...lol
it roughly correlates to airflow (not necessarily boost) i.e. MAF reading.
 

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Do you back off when you get that surge? I have noticed the v6 motor (and probably the 4cyl as well) is very touchy about overboost. If you do back off, try doing it again, but this time keep the throttle applied. if it truly is overboosting, it will throw the car into limp mode and pop up a code. Then you will know for sure if it's the boost controller or not.
My only experience with overboost was a boost spike, then BAM. flat on its face from fuel cut, but it was after I swapped the turbo...adjusted the wastegate arm and it was fine...but it has to be something other than overboost if the wastegate was never tampered with, and he's never had that issue before. especially if the car is still stock and has been that way
 

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it roughly correlates to airflow (not necessarily boost) i.e. MAF reading.
hmmmm....maybe its not getting the right reading and you can even see it through that gauge when it starts bouncing around? wild guess, but if it hasn't been cleaned in awhile it should be done anyways, takes like 2 mins.

I'd clean the MAF, reset the ECU and see how it does
 

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Discussion Starter · #13 ·
All good information. Thank you!

I will start with replacing the BCV.

Though this car has 126K on it, I just completed a rather extensive tune up.

The car purrs at an idle.

I will order and install the BCV and update the outcome once I drive it after the fact.


Thanks again!
 

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All good information. Thank you!

I will start with replacing the BCV.

Though this car has 126K on it, I just completed a rather extensive tune up.

The car purrs at an idle.

I will order and install the BCV and update the outcome once I drive it after the fact.


Thanks again!
What's an extensive tune up consist of? All new coil packs and plugs? What else?
 

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Discussion Starter · #15 ·
Well, besides a new clutch, clutch slave, clutch master and fly wheel - I did the serpentine belt, all tensioners, coil packs, plugs, alternator, water pump, coolant flush, fuel pump (it started to fail), and fuel filter
 

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Discussion Starter · #16 ·
so..... yesterday all of my parts came in.

I replaced my BSR intake filter (the old one was kinda dirty).
I cleaned my MAF over and over and over and over again.
I also replaced the BCV.

I drove this car about 400 miles today from Providence, RI to Newark, NJ to NYC. Car drove smoother than ever!!

I purchased the replacement filter through GenuineSaab.com
I purchased the BCV through SAABPartsUSA.com
The MAF cleaner I bought from PepBoys.

The worst part about this was locating the 5-point security torx bit needed to remove the MAF.

(Pepboys was my last stop) - they had the bit; however, I had to spend ~$36 on the "tool kit" in order to obtain it.

Sears, Grainger, AutoZone, and Home Depot did not have the bit.
 

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Harbor Freight has a kit like this for $9.99 minus 20% coupon. They make cheap tools, but for something like this that you rarely use and don't apply much pressure to, they are perfect!


Sean
 

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Well, besides a new clutch, clutch slave, clutch master and fly wheel - I did the serpentine belt, all tensioners, coil packs, plugs, alternator, water pump, coolant flush, fuel pump (it started to fail), and fuel filter
Damn...those are repairs not a tune up:eek: Why the alternator and water pump.
And the US spec cars don't have fuel filters--what's the deal here?
 
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